There is no consensus on what degree of angulation justifies a diagnosis, an incline between 15° and 30° is typical. A similar-sounding term, camptodactyly, is a fixed flexion deformity of a digit.

Ainhum is an acquired and progressive condition, and thus differs from congenital annular constrictions. Ainhum has been much confused with similar constrictions caused by other diseases such as leprosy, diabetic gangrene, syringomyelia, scleroderma or Vohwinkel syndrome. In this case, it is called pseudo-ainhum, treatable with minor surgery or intralesional corticosteroids, as with ainhum. It has even been seen in psoriasis or it is acquired by the wrapping toes, penis or nipple with hairs, threads or fibers. Oral retinoids, such as tretinoin, and antifibrotic agents like tranilast have been tested for pseudo-ainhum. Impending amputation in Vohwinkel syndrome can sometimes be aborted by therapy with oral etretinate. It is rarely seen in the United States but often discussed in the international medical literature.

Soft tissue constriction on the medial aspect of the fifth toe is the most frequently presented radiological sign in the early stages. Distal swelling of the toe is considered to be a feature of the disease. In grade III lesions osteolysis is seen in the region of the proximal interphalangeal joint with a characteristic tapering effect. Dispersal of the head of the proximal phalanx is frequently seen. Finally, after autoamputation, the base of the proximal phalanx remains. Radiological examination allows early diagnosis and staging of ainhum. Early diagnosis is crucial to prevent amputation.

Doppler shows decreased blood flow in posterior tibial artery.

Webbed toes can be separated through surgery. Surgical separation of webbed toes is an example of body modification.

As with any form of surgery, there are risks of complications.

The end results depend on the extent of the webbing and underlying bone structure. There is usually some degree of scarring, and skin grafts may be required. In rare instances, nerve damage may lead to loss of feeling in the toes and a tingling sensation. There are also reports of partial web grow-back. The skin grafts needed to fill in the space between the toes can lead to additional scars in the places where the skin is removed.

Due to a developmental arrest there is an abnormal alignment of the joint surfaces at either interphalangeal joint causing angulation in the plane of the palm. The finger may be slightly bent or have a very prominent bend.

Diagnosis is based on physical examination including radiographs of the hands and feet and imaging studies of the kidneys, bladder, and female reproductive tract. HOXA13 is the only gene known to be associated with HFGS. Approximately 60% of mutations are polyalanine expansions. Molecular genetic testing is clinically available.

The main diagnostic tools for evaluating FND are X-rays and CT-scans of the skull. These tools could display any possible intracranial pathology in FND. For example, CT can be used to reveal widening of nasal bones. Diagnostics are mainly used before reconstructive surgery, for proper planning and preparation.

Prenatally, various features of FND (such as hypertelorism) can be recognized using ultrasound techniques. However, only three cases of FND have been diagnosed based on a prenatal ultrasound.

Other conditions may also show symptoms of FND. For example, there are other syndromes that also represent with hypertelorism. Furthermore, disorders like an intracranial cyst can affect the frontonasal region, which can lead to symptoms similar to FND. Therefore, other options should always be considered in the differential diagnosis.

Some recommend avulsion of the nail plate with surgical destruction of the nail matrix with phenol or the carbon dioxide laser, if the blood supply is good.

The exact cause of the condition is unknown. In some cases, close family members may share this condition. In other cases, no other related persons have this condition. The scientific name for the condition is syndactyly, although this term covers both webbed fingers and webbed toes. Syndactyly occurs when apoptosis or programmed cell death during gestation is absent or incomplete. Webbed toes occur most commonly in the following circumstances:

- Syndactyly or Familial Syndactyly

- Down syndrome

It is also associated with a number of rare conditions, notably:

- Aarskog–Scott syndrome

- Acrocallosal syndrome

- Apert's syndrome

- Bardet-Biedl syndrome

- Carpenter syndrome

- Cornelia de Lange syndrome

- Edwards syndrome

- Jackson–Weiss syndrome

- Fetal hydantoin syndrome

- Miller syndrome

- Pfeiffer syndrome

- Smith-Lemli-Opitz syndrome

- Timothy syndrome

- Ectodermal Dysplasia

- Klippel-Feil Syndrome

Additional findings that may be present in HFGS according to the latest research are:

- Limited metacarpophalangeal flexion of the thumb or limited ability to oppose the thumb and fifth finger

- Hypoplastic thenar eminences

- Medial deviation of the great toe (hallux varus), a useful diagnostic sign when present

- Small great toenail

- Fifth-finger clinodactyly, secondary to a shortened middle phalanx

- Short feet

- Altered dermatoglyphics of the hands; when present, primarily involving distal placement of the axial triradius, lack of thenar or hypothenar patterning, low arches on the thumbs, thin ulnar loops (deficiency of radial loops and whorls), and a greatly reduced ridge count on the fingers

Radiographic findings

- Hypoplasia of the distal phalanx and first metacarpal of the thumbs and great toes

- Pointed distal phalanges of the thumb

- Lack of normal tufting of the distal phalanges of the great toes

- Fusions of the cuneiform to other tarsal bones or trapezium-scaphoid fusion of the carpals

- Short calcaneus

- Occasional bony fusions of the middle and distal phalanges of the second, third, fourth, or fifth toes

- Delayed carpal or tarsal maturation

- Metacarpophalangeal profile reflecting shortening of the first metacarpal, the first and second phalanges, and the second phalanx of the second and fifth digits

Urogenital Defects

Females may have the following:

- Vesicoureteral reflux secondary to ureteric incompetence

- Ectopic ureteral orifices

- Trigonal hypoplasia

- Hypospadiac urethra

- Subsymphyseal epispadias

- Patulous urethra

- Urinary incontinence (related to structural anomalies and weakness of the bladder sphincter muscle)

- Small hymenal opening

- Various degrees of incomplete Müllerian fusion with or without two cervices or a longitudinal vaginal septum

Males may have the following:

- Retrograde ejaculation (related to structural anomalies and weakness of the bladder sphincter muscle)

Most of these conditions are self-correcting during childhood. In the worst cases, surgery may be needed. Most of the time, this involves lengthening the Achilles tendon. Less severe treatment options for pigeon toe include keeping a child from crossing his or her legs, use of corrective shoes, and casting of the foot and lower legs, which is normally done before the child reaches 12 months of age or older.

If the pigeon toe is mild and close to the center, treatment may not be necessary.

Ballet has been used as a treatment for mild cases. Dance exercises can help to bend the legs outward.

Diagnosis of clubfoot deformity is by physical examination. Typically, a newborn is examined shortly after delivery with a head to toe assessment. Examination of the lower extremity and foot reveals the deformity, which may affect one or both feet. Examination of the foot shows four components of deformity.

- First, there is a higher arch on the inside of the foot. This component of the deformity can occur without the other aspects of clubfoot deformity. In isolation, this aspect of the deformity is called cavus deformity.

- Second, the forefoot is curved inward or medially (toward the big toe). This component of the deformity can occur without the other aspects of clubfoot deformity. In isolation, this aspect of the deformity is called metatarsus adductus.

- Third, the heel is turned inward. This is a natural motion of the heel and subtalar joint, typically referred to as inversion. In clubfoot deformity, the turning in (inversion) of the heel is fixed (not passively correctable) and considered a varus deformity.

- Fourth, and finally, the ankle is pointed downward. This is a natural motion of the ankle referred to as plantar flexion. In clubfoot deformity, this position is fixed (not correctable) and is referred to as equinus deformity.

A foot that shows all four components are diagnosed as having clubfoot deformity. These four components of a clubfoot deformity can be remembered with the acronym CAVE (cavus, forefoot adductus, varus, and equinus).

The severity of the deformity can also be assessed on physical exam, but is subjective to quantify. One way to assess severity is based on the stiffness of the deformity or how much it can be corrected with manual manipulation of the foot to bring it into a corrected position. Other factors used to assess severity include the presence of skin creases in the arch and at the heel and poor muscle consistency.

In some cases, it may be possible to detect the disease prior to birth during a prenatal ultrasound. Prenatal diagnosis by ultrasound can allow parents the opportunity to get information about this condition and make plans for treatment after their baby is born.

Other testing and imaging is typically not needed. Further testing may be needed if there are concerns for other associated conditions.

Three main support groups of this syndrome are the ASGA in Australia, The Association for Children with Genetic Disorders in Poland, and the Association of People of Genetic Disorders in Greece.

Autosomal recessive inheritance is the most likely, but sporadic mutations and autosomal dominant cases may also occur.

This syndrome has been associated with mutations in the ARID1B gene.

Mutations in SOX11 are associated to this syndrome.

The diagnosis is generally based on the presence of major and at least one minor clinical sign and can be confirmed by molecular genetic testing of the causative genes. Recent studies revealed that fifth finger nail/distal phalanx hypoplasia or aplasia is not a mandatory finding.

Severe congenital onychogryphosis affecting all twenty nailbeds has been recorded in two families who exhibit the dominant allele for a certain gene. Congenital onychogryphosis of the fifth toe (the little toe) is fairly common, but asymptomatic and seldom brought to the attention of medical professionals. Rather, it is brought to the attention of manicurists who routinely file the clawed toenail flat.

If non-operative treatments are unsuccessful or achieve incomplete correction of the deformity, surgery is sometimes needed. Surgery was more common prior to the widespread acceptance of the Ponseti Method. The extent of surgery depends on the severity of the deformity. Usually, surgery is done at 9 to 12 months of age and the goal is to correct all the components of the clubfoot deformity at the time of surgery.

For feet with the typical components of deformity (cavus, forefoot adductus, hindfoot varus, and ankle equinus), the typical procedure is a Posteromedial Release (PMR) surgery. This is done through an incision across the medial side of the foot and ankle, that extends posteriorly, and sometimes around to the lateral side of the foot. In this procedure, it is typically necessary to release (cut) or lengthen the plantar fascia, several tendons, and joint capsules/ligaments. Typically, the important structures are exposed and then sequentially released until the foot can be brought to an appropriate plantigrade position. Specifically, it is important to bring the ankle to neutral, the heel into neutral, the midfoot aligned with the hindfoot (navicula aligned with the talus, and the cuboid aligned with the calcaneus). Once these joints can be aligned, thin wires are usually placed across these joints to hold them in the corrected position. These wires are temporary and left out through the skin for removal after 3–4 weeks. Once the joints are aligned, tendons (typically the Achilles, posterior tibialis, and flexor halluces longus) are repaired at an appropriate length. The incision (or incisions) are closed with dissolvable sutures. The foot is then casted in the corrected position for 6–8 weeks. It is common to do a cast change with anesthesia after 3–4 weeks, so that pins can be removed and a mold can be made to fabricate a custom AFO brace. The new cast is left in place until the AFO is available. When the cast is removed, the AFO is worn to prevent the foot from returning to the old position.

For feet with partial correction of deformity with non-operative treatment, surgery may be less extensive and may involve only the posterior part of the foot and ankle. This might be called a posterior release. This is done through a smaller incision and may involve releasing only the posterior capsule of the ankle and subtalar joints, along with lengthening the Achilles tendon.

Surgery leaves residual scar tissue and typically there is more stiffness and weakness than with nonsurgical treatment. As the foot grows, there is potential for asymmetric growth that can result in recurrence of foot deformity that can affect the forefoot, midfoot, or hindfoot. Many patients do fine, but some require orthotics or additional surgeries. Long-term studies of adults with post-surgical clubfeet, especially those needing multiple surgeries, show that they may not fare as well in the long term, according to Dobbs, et al. Some patients may require additional surgeries as they age, though there is some dispute as to the effectiveness of such surgeries, in light of the prevalence of scar tissue present from earlier surgeries.

Bunion can be diagnosed and analyzed by plain projectional radiography. The "hallux valgus angle" (HVA) is the angle between the longitudinal axes of the proximal phalanx and the first metatarsal bone of the big toe. It is considered abnormal if greater than 15–18°. The following HVA angles can also be used to grade the severity of hallux valgus:

- Mild: 15–20°

- Moderate: 21–39°

- Severe: ≥ 40°

The "intermetatarsal angle" (IMA) is the angle between the longitudinal axes of the first and second metatarsal bones, and is normally less than 9°. The IMA angle can also grade the severity of hallux valgus as:

- Mild: 9–11°

- Moderate: 12–17°

- Severe: ≥ 18°

A doctor will typically evaluate whether there is bilateral (both legs) toe walking, what the child's range of motion is (how far they can flex their feet) and perform a basic neurological exam. Treatment will depend on the cause of the condition.

The accessory nail of the fifth toe is a physical trait of the small toe, where a minuscule "sixth toenail" is present in the outer corner of the nail situated on the smallest toe. It is commonly perceived to be especially prevalent amongst Han Chinese;.

Non-surgical therapies include:

- Shoe modifications: wearing shoes that have a wide toe box, and avoiding those with pointed toes or high heels.

- Oral nonsteroidal anti-inflammatory drugs may help in relieving the pain and inflammation.

- Injections of corticosteroid are commonly used to treat the inflammation.

- Bunionette pads placed over the affected area may help reduce pain.

- An ice pack may be applied to reduce pain and inflammation.

Surgery is often considered when pain continues for a long period with no improvement in these non-surgical therapies.

The treatment of an ingrown toenail partly depends on its severity.

Coffin–Siris Syndrome is a rare genetic disorder that causes developmental delays and absent fifth finger and toe nails.

There had been 31 reported cases by 1991. The numbers of occurrence since then has grown and is reported to be around 80.

The differential includes Nicolaides–Baraitser syndrome.

Mild to moderate cases are often treated conservatively with warm water and epsom salt soaks, antibacterial ointment and the use of dental floss. If conservative treatment of a minor ingrown toenail does not succeed, or if the ingrown toenail is severe, surgical treatment may be required. A "gutter splint" may be improvised by slicing a cotton-tipped wooden applicator diagonally to form a bevel and using this to insert a wisp of cotton from the applicator head under the nail to lift it from the underlying skin after a foot soak.

Some individuals have preaxial polydactyly in the feet (unilateral in one, bilateral in 13), consisting of a small extra biphalangeal toe, in most cases with an associated rudimentary extra metatarsal, lying in a soft tissue web between the hallux and second toe. In some cases, this was accompanied by hypoplasia of the head of the first metatarsal and absence of both phalanges of the hallux.

Diagnosis by a doctor’s examination is the most common, often confirmed by x-rays. X-ray is used to display the fracture and the angulations of the fracture. A CT scan may be done in very rare cases to provide a more detailed picture.